The present invention relates to a stress detecting and measuring method, wherein in order to measure a shearing strain alone associated with a stress acting in an intended direction, said stress being one of the stresses produced in an axle of a vehicle such as a transporting machine, e.g., an automobile, airplane or railroad vehicle, and in a structure having a fixed support point adjacent the axle, the conditions for the optimum position (neutral spot) where a stress sensor is to be mounted are indicated, and it also relates to a stress detecting method and a stress detecting device, adapted to accurately measure a shearing strain alone associated with a stress acting in an intended direction by further separating a plurality of stresses acting on the stress sensor.
As for methods for measuring stresses, strains or the like acting on a transporting machine, such as an automobile, airplane or railroad vehicle, mention may be made of the photoelasticity method, brittle coating method, caustic method, holographic method and strain gauge method, of which generally the strain gauge method has been used most frequently.
The strain gauge method is convenient to use since a variety of strain gauges are available. In this method, a strain gauge is used for stress measurement by being built in a transducer to serve as a stress sensor. If necessary, a plurality of strain gauges are attached to a vehicle or a structure adjacent an axle. In this method, however, the sensor is subjected to the stresses acting on the strain gauge in any direction; therefore, analysis is necessary, and it is difficult to measure a shearing strain alone associated with a stress acting in an intended direction. Few of the stress sensors using strain gauges are capable of cancelling all but one shearing strain acting in an intended direction, and there is no perfect one.